• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2275-2282
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• 1999

In ATM networks, bandwidth allocation using available bandwidth is important to control ABR traffic efficiently. However, it is difficult to dynamically assign bandwidth on bursty traffic, because the tracking of the existing available bandwidth information uses statistical value. In this paper, we propose a output-bufferd ATM switch using Per-VC queueing scheme with timer and Controller. The controller determines whether each VC is in congestion state or not, and the timer can assign dynamically as determining the available bandwidth for the Present period by Backlogged time and total link capacity, and then transmitting the determined bandwidth to source. Instead of using statistical parameters, the proposed scheme can improve link efficiency as allocating the bandwidth of the next period, by use of measured bandwidth during the current period.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1177-1186
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• 2003

The multimedia ad hoc wireless network is quite an attractive issue since it offers a flexible solution to enable delivery of multimedia services to mobile end users without fixed backbone networks. However, with the unique design challenges of ad hoc wireless networks, it is a non-trivial issue to provide bounded delay guarantee, with fair share of resources. In this paper, we implemented the delay guaranteed fair queueing (DGFQ) scheme distributively. Through the results of performance evaluation, we can conclude that DGFQ also performs well to control bounded delay in multimedia ad hoc wireless networks.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.259-262
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• 2006

라우터에서 세션간 출력링크 용량을 공정하게 분배하기 위해, Generalized Processor Sharing(GPS) 기반 공정큐잉 알고리즘들이 제안되었다. 이 알고리즘들은 대역폭 관점에서는 서버에 대기중인 각 세션들에게 공정한 서비스를 제공해 주지만, 지연 관점에서는 경계치 이하로 보장해 주는 서비스만 제공한다. 이로 인해 적은 양의 패킷을 생성하는 세션이라도 작은 지연으로 서비스 받고자 한다면, 큰 대역폭을 할당받아야 하는 문제가 발생한다. 이와 같이 지연과 대역폭이 결합됨으로 써 생기는 문제를 해결하고자 서비스커브 기반의 알고리즘이 제안되었지만, 이 알고리즘들은 서비스 지연과 대역폭간 제한된 분리밖에 지원하지 못한다. 본 논문에서는 서비스 지연과 대역폭을 분리하여 독립적으로 처리함으로 써, 각 세션에게 세션의 트래픽 특성에 맞게 서비스를 제공해 주는 지연-대역폭 정규화 모델을 제안한다. 이 모델은 서비스를 서비스 지연과 대역폭 측면에서 정의하고, 정의된 서비스를 서비스 가치(Value of Service: VoS)라는 개념을 통해 표현한다. 이 모델과 VoS개념을 이용하여 각 세션에게 지연-대역폭 관점에서 공정한 서비스를 제공하는 스케줄링 알고리즘을 제안한다. 이 알고리즘을 통해, 각 세션에게 지연-대역폭 관점에서 공정서비스, 전송률을 보장하는 서비스를 제공하려고 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.149-152
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• 2011

본 논문에서는 무선 메쉬 네트워크에서 H.264 비디오 코딩을 이용한 대화형 멀티미디어 전송시 서비스 품질을 향상시키기 위한 Early Drop 기법을 제안한다. Early Drop 기법은 비디오 프레임의 재생시간과 H.264로 부호화된 비디오 프레임의 중요도를 고려하여 네트워크 혼잡 시 발생하는 큐잉 지연과 큐 오버플로우로 인한 비디오 서비스 품질 저하를 효과적으로 개선하기 위해 개발되었다. 계층간 최적화(Cross-Layer)기법을 사용하여 각 비디오 패킷 별로 재생시간까지 남은 시간을 의미하는 delay budget을 할당하고 전송 중 재생시간 초과로 인해 목적지 노드에서 재생되지 못하는 비디오 패킷을 전송 초기 손실 시켜 무선대역폭 낭비와 전송 지연을 최소화 한다. 또한, H.264 비디오 프레임 종류별 중요도를 고려하여 차별화 된 delay budget을 할당해 중요도가 높은 비디오 프레임의 전송을 보장하여 비디오 전송 품질을 높인다. 성능 검증을 통해 네트워크 혼잡 시 Early Drop 기법은 기존에 제안된 IEEE 802.11e 기반의 H.264 비디오 전송기법과 비교하여 전송지연과 프레임 손실률을 최소화해 향상된 비디오 품질을 보였다.

• Journal of Internet Computing and Services
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• v.9 no.2
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• pp.15-23
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• 2008

This paper proposes the new structural MOQ(Multiple Input/Output-Queued) switch which guarantees QoS while maintaining high efficiency and deals with the Anti-Empty algorithm which is new arbitration algorithm to be used for the proposed switch. The new structure of the proposed switch based on MIQ, MOQ is designed to have the same buffer speed as the external line speed. Also, the proposed switch makes it possible to remove the weak point of existing methods and introduces the new method of the MOQ operation to support QoS. Therefore, this switch is equal to the Output Queued switch in efficiency and delay, and guarantees the high-speed switching supporting QoS without cell loss.

• Journal of the Korea Society of Computer and Information
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• v.5 no.4
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• pp.82-89
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• 2000

This study analyzes the cell loss probability of an ATM multiplexer with real time and non-real time bursty traffics. It is assumed that an ATM multiplexer with loss priority control for the analysis. The loss priority control uses the CLP Reld of cell header. For easy analysis and less computation. the multiplexed traffic of the ATM multiplexer was modeled by the MMDP. The ATM multiplexer is simulated by the MMDP/MMDP/l/K queueing system. From the above results, The connection admission of an ATM multiplexer with loss priority control is determined by the cell loss probability with low priority as well as the size of threshold buffer. Therefore, to increase the statistical multiplexing gain it will be good to utilize the loss priority control in order.

• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.331-338
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• 2006

Most fair packet schedulers supporting quality-of-services of real-time multimedia applications are based on the finish time design scheme in which the expected transmission finish time of each packet is used as its timestamp. This scheme can adjust the latency of a flow with raising the flow's scheduling rate but it may suffer from severe bandwidth loss due to the coupled rate and delay allocation. This paper first introduces the concept of delay resource, and then proposes a scheduling method to improve the bandwidth utilization in which delay resource being lost due to the coupled allocation is transformed into bandwidth one. The performance evaluation shows that the proposed method gives higher bandwidth utilization by up to 50%.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.5
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• pp.3-11
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• 2005

This paper presents a performance analysis model based on an M/M/1 queue and Poisson distribution of input data traffic. The simulation on a pipelined AES system with processing rate of 10 rounds per clock shows $4.0\%$ higher performance than a non-pipelined version consuming 10 clocks per transaction. Physical implementation of pipelined AES with FPGA takes 3.5 times bigger gate counts than the non-pipelined version whereas the pipelined version yields only $3.5\%$ performance enhancement. The proposed analysis model can be used to optimize cost-performance of AES hardware designs.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.187-193
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• 2015

The ICT healing platform sets a couple of goals including preventing chronic diseases and sending out early disease warnings based on personal information such as bio-signals and life habits. The 2-step open system(TOS) had a relay designed between the healing platform and the storage of personal health data. It also took into account a publish/subscribe(pub/sub) service based on large-scale connections to transmit(monitor) the data processing process in real time. In the early design of TOS pub/sub, however, the same buffers were allocated regardless of connection idling and type of message in order to encode connection messages into a deflate algorithm. Proposed in this study, the dynamic buffer allocation was performed as follows: the message transmission type of each connection was first put to queuing; each queue was extracted for its feature, computed, and converted into vector through tf-idf, then being entered into a k-means cluster and forming a cluster; connections categorized under a certain cluster would re-allocate the resources according to the resource table of the cluster; the centroid of each cluster would select a queuing pattern to represent the cluster in advance and present it as a resource reference table(encoding efficiency by the buffer sizes); and the proposed design would perform trade-off between the calculation resources and the network bandwidth for cluster and feature calculations to efficiently allocate the encoding buffer resources of TOS to the network connections, thus contributing to the increased tps(number of real-time data processing and monitoring connections per unit hour) of TOS.

• The Journal of the Korea Contents Association
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• v.8 no.12
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• pp.28-36
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• 2008

In this paper, a service mobility scheme using user's location & service information table management and user recognition skill is proposed to support the movement of the multimedia service user and provide the seamless multimedia service environment in home network. We analyzed the proposed scheme using queueing system and we built test bed for experiment onthe proposed scheme to verify the operation and performance. As a result, we can show the proposed scheme provides a seamless multimedia service through the new client terminal when a user move to the new location and shows the performance completing the service mobility through the new client terminal within the service delay time which is shorter than the service delay time generated in the previous scheme.